Taylor Swift's 1989 has sold more than five million copies, spawned five Top 10 singles (and counting), and launched the most celebrity-studded pop tour of all time. Since the day it was released in October 2014, it's been the safe bet to win Album of the Year at this year's Grammys.

I'm here to tell you why it won't.

No, the top honor at Monday's 58th Grammy Awards (8 p.m., CBS) will go to rapper Kendrick Lamar's To Pimp a Butterfly.

Some might not see that as a monumental upset, considering Lamar's dense, funky album was also widely acclaimed. But Swift is perhaps the world's biggest pop star, and some online oddsmakers have given her 2-5 odds to take the top trophy. She is without question the favorite.

The Grammys have a long history of baffling choices, so there's every chance Album of the Year could still go to Chris Stapleton's Traveller, Alabama Shakes' Sound & Color or the Weeknd's Beauty Behind the Madness. But I see this is a two-horse race, and I'm betting on Kendrick to win. Here are six reasons why.

1. Butterfly was the best-reviewed album of 2015 — and it wasn't even close. Normally, critical acclaim is only one factor in Grammy voting, and in some cases it doesn't factor in at all. But it's been years since there was such a consensus around one album as the year's best. Rolling Stone, Billboard, the New York Times, Pitchfork, Entertainment Weekly, the Village Voice, the Guardian and, ahem, the Tampa Bay Times are among the many publications who crowned Butterfly the No. 1 album of 2015. Every year has its darlings, but acclaim that universal is unheard of. Grammy voters cannot, and will not, ignore it.

2. Butterfly was a hit, too. It hasn't sold a million copies, but To Pimp a Butterfly did debut at No. 1, moving 324,000 copies in its first week. Singles Alright, King Kunta and The Blacker the Berry were modest hits but had significant cultural penetration. Throw a slew of high-profile performances, like a headlining gig at Bonnaroo and a one-nighter with the National Symphony Orchestra at the Kennedy Center, and it's safe to say Lamar flew under no one's radar in 2015.

3. Butterfly is socially relevant. Swift brought her usual lyrical honesty to 1989, but it was nothing compared to the brutal truths on Lamar's novelistic LP, which grapples with race, gender, fame, class and the complicated morals of his Compton, Calif., upbringing. There's a reason Alright evolved into a Black Lives Matter protest anthem — the song, and the album as a whole, captured so much of the frustration and complexity of African-American life in 2015.

4. The Grammys love a good tribute. To Pimp a Butterfly features cameos from George Clinton and Ronald Isley, and samples mid '70s tracks by James Brown, Sly and the Family Stone, the Isley Brothers and Fela Kuti. That sort of crate-digging reverence paid off for Daft Punk, whose Random Access Memories won Album of the Year in 2014.

5. Lamar is overdue, and Swift is … not. Like it or not, the "overdue/under-due" factor still plays a big role in deciding major awards. Lamar was nominated for Album of the Year in 2014 for Good Kid, M.A.A.D. City, but wasn't expected to win — but he was expected to win Best Rap Album, which he lost to Macklemore and Ryan Lewis, an upset rap fans are still howling about. Swift, meanwhile, won Album of the Year in 2010, for Fearless, and if 1989 wins again, she'd be the first solo female act to win twice — all by age 26. Sadly, that'll give some Grammy voters pause.

6. The Adele factor. In October, Swift's towering celebrity and success seemed untouchable; 1989 was at that point 2015's best-selling album. Then came Adele and 25, which dwarfed anything Swift has ever done — 25 sold more copies in one week than 1989 did in two months. While Hello and 25 won't be eligible for Grammys until 2017, there's no question Adele's more recent success has dimmed 1989's once-blinding glimmer.